The subject matter disclosed herein relates to a turbine casing. Specifically, the subject matter disclosed herein relates to a steam turbine casing including a ledge ring partition aperture (or, cutout), allowing for a flush interface between an extraction conduit and a ledge ring.
Conventional turbine casing segments (e.g., in low-pressure, or LP, steam turbine casing segments) include built-up interfaces, commonly referred to as extraction boxes, for connecting extraction conduits to the casing segment. Typically, each extraction conduit has a wider diameter than the axial length of its respective turbine stage. The extraction box provides an interface between the wider extraction conduit and the narrower turbine stage casing segment, such that a desired amount of working fluid (e.g., steam) may be extracted from the desired stage of the turbine.
In some turbine applications, incorporating extraction boxes into the turbine casing may be impracticable. For example, in some cases, extraction boxes may occupy an undesirable amount of space in the casing segment, and may complicate the fabrication of the casing segment.